Despite being a big Metroid fan, I've never actually read the manga, I just know the lore from it.
I'll just have to finally rectify that. From what I can tell, though, your understanding of things is quite accurate, with only a couple potential mistakes (?):
1.) Did the Thoha really create the Metroids
after Samus had already grown up and become a bounty hunter? I was under the impression that they were older than that, but if they were, it would mean Raven Beak had to have been working for quite some time to contain the pandemic. Even if the Metroids were created that recently, though, it still took him awhile to get a hold on things, being that Samus went on multiple successful missions, during that timeframe. I guess it makes sense, being that we know how deadly the X are, and that Raven Beak didn't have the benefit of a Metroid vaccine, the way Samus did, so he had to be extra cautious.
2.) I don't think Raven Beak had any involvement with Ridley, or the Space Pirates. If he did, we don't know that for certain, as the game doesn't tell us. It actually seems more likely he had nothing to do with them, as Kraid is one of the high ranking members of the organization, yet the Mawkin have him restrained like a wild animal. It seems that, as of Super, and the aftermath of those events depicted in Fusion and Dread, the Space Pirates have been quite thoroughly decimated. Mother Brain and Ridley are permadead, Zebes is gone, and Samus did a great job thinning Space Pirate numbers across the galaxy in the Prime games, as well. I'm excited for a new type of villain, in Sylux!